Drill bit



April 7, 1964 c. L.. DEI-:LY 3,127,946

DRILL BIT Filed May 1, 1961 IN V EN TOR. HHWZ/L L. EEZ Y l an 24 A.. n l 40 4' W mi Huw? United States Patent O 3,127,946 DRiLL BIT Carroll lL. Deely, 6210 N. Central Expressway, Dallas 6, Tex. Filed May 1, 1961, Ser. No. 106,606 6 Claims. (Cl. V75-4M) This invention relates to rotary drill bits for drilling bore holes in earth formations, and more particularly to a drill bit which utilizes hard abrading elements, such as diamonds or the like, for performing the cutting or abrading action on the earth formation.

With more particularity, this invention is directed to a drill bit which utilizes the abrading elements, such as diamonds, in such manner as to obtain a high degree of cutting etiiciency with the minimum wear and/ or decomposition of the abrading elements and of the material which bonds the abrading elements to the bit body.

Various drill bits, embodying diamond or other hard abrading elements as insets, have been proposed heretofore, but these could not operate over long periods of time without showing definite wear and disintegration. It is to counteract such difficulties that the present bit has been designed, which bit will give longer wearing qualities to the abrading elements and better cutting action of the bit, than diamond bits heretofore in use. The present design also provides a bit, the cutting load on which, is more evenly distributed on the diamonds or abrading elements, thereby giving maximum wear thereto.

The present bit is so designed as to form a substantially annular ring at the lower end thereof, so as to cut a core, thereby relieving the center of the bit of the wear usually incident to bits which have uniformly set abrading elements across the lower face thereof. The present bit is so constructed that the center of the formation being cut extends up into the bit body to form a core, so as to enable the core to be subsequently broken olf and discharged upward in the fluid stream to be carried to the top of the bore hole without having to disintegrate this particular portion of the formation.

The present bit is also designed to give maximum circulation of drilling fluid to the cutting faces thereof, so as to flush the abraded formation particles from the cutting face of the bit, and at the same time, provide a coolant for the abrading elements, such as diamonds, tungsten carbide, or other hard abrasive elements.

In the present invention, the drill bit comprises a body portion having a threaded cylindrical shank, which threaded shank portion usually has a tapered tool joint threaded thereon, the threads of which may be male or female, in accordance with the particular string of drill stem on which the bit is to be used. The body portion of the present bit is enlarged immediately below the threaded shank portion, which enlarged portion is Substantially cylindrical in shape and has fluid passages formed around the periphery thereof in side-by-side relation, as will be more fully brought out hereinafter. From the extreme outside diameter of the cylindrical portion of the bit body, which will cut a full gauge size bore hole, the body tapers inwardly and downwardly in a frusto-conical form, and it is inset with abrading elements, as `is the cylindrical portion which cuts lthe gauge size bore hole. The lower end of the bit body is slightly concave in that it has a slight, inversely arranged hollow cone portion, with the axis of the bit body being the center of the cone, which conical cavity lgives stability to the bit when the bit is cut-ting on the bottom of the bore hole.

The present bit has an axial opening in the upper portion of the shank and body, which axial opening joins li Patented Apr. 7, 1964 ICC with a plurality of interiorly arranged branch outlets, which outlets terminate on the lower face of the bit and interconnect with circulation channels formed exteriorly on the bit body, so as to direct the circulating iluid from Ithe axial opening in the drill bit to the abrading surfaces of the drill bit in such manner as to give substantially even distribution to the circulating Huid over the entire surface of the bit which is inset with abrading elements.

The present bit is shown to have four outlet passages which will supply `fluid to the four cutting segments of the bit, as iiuid under a given pressure will be supplied to a given area through the lateral surface grooves, which grooves are of given cross-sectional area. However, smaller diamond bits may be supplied with fewer fluid passages, although it has been found that three passages and three surface segments are a preferred minimum. However, as the size of the bit becomes larger, tive or more such fluid passages and five or more surface segments may be utilized. It is preferable to have the surface segments of the bit divided by deeper fluid passages, which increase in cross-sectional area as they extend outward and upward along the side of the bit body. However, a closed, lateral passage connects with the upper end of the core passage, the outer end of which closed, lateral passage extends into an open grooved passage, which open grooved passage extends upward along the side of the bit body and is of such cross-sectional area that any formation core which is broken off will be discharged outward through the lateral passage and upward through the lgroove on the side of lthe bit body. `ln this manner, the portion of formation usually designated as the core, does not have to be ground into tinely comminuted powder in order to be discharged upward into the fluid stream to be carried as broken core particles to the top of the bore hole.

The present bit is so designed that, when secured to the lower end of a rotary `drill stem, the bit will become centered, due to the relatively shallow conical lower face,

the apex of which conical lower face is in axial alignment with the rotational axis of the bit so upon rotation of the rotary drill stem, the bit will out a hole in the earth formation of a size of the lower end of the bit, and as the bit eats into the formation, the hole will be reamed by the steeply tapered sides of the bit until the hole is of gauge size, as defined by the cylindrical portion of the bit, which is `also inset with abrading elements. This enables a new hole to be speedily cut in the earth formation without the necessity of having to ream a small hole to a larger hole, however, it is so designed that the bit can be ru-n into a small hole in the earth formation and readily reamed to a larger, full gauge size hole, and when the bottom of the smaller hole yis reached, the ydrilling of the new hole and the reaming "thereof may be continued simultaneously and with the same bit, without having to change the bit.

An object of this invention is to provide `a bit of the character which utilizes diamonds or other hard -abrading elements set along the face thereof which is normally in contact with the formation being cut in such manner that the weight and the cutting action are substantially equally distributed over the entire cutting `face of the bit which is inset 'with diamonds or other hard abrading elements.

Another object of the invention is to provide a drill bit which will cut and break off a core when a predetermined amount of core is cut, and which will discharge the core into a fluid passage fwhich leads to the top of the bore hole of the well without having to regrind the core into ne cuttings.

Still another object of this invention is to provide, in a drill bit, a fluid conduit system whereby a coolant fluid at high pressure may be supplied to several points on El the cutting face of the bit body so as to maintain the abrading elements in cooled condition.

A yet further object of this invention is to provide a bit body with a relatively long tapered portion, which will enable a greater number of abrading elements to be inset therein which will act upon the formation for a given cross-sectional area of the bore hole.

With these objects in mind and others which will become manifest as the description proceeds, reference is to be had to the accompanying drawings in which like reference characters designate like parts in the several views thereof, in which:

FIG. 1 is a side elevational view of a bit body shown apart from a string of drill pipe, and showing the abrading elements thereon and the lateral, core discharge opening in a side thereof;

FIG. 2 is a sectional view taken on the line 2-2 of FIG. l, looking in the direction indicated by the arrows;

FIG. 3 is a sectional view taken on the line 3 3 of FIG. 2, looking in the direction indicated by the arrows, with a portion of the body being broken away so as to expose a closed passage therein;

`lilG. 4 is a transverse, cross-sectional view taken on the line 4 4- of FIG. l, looking in the direction indicated by the arrows; and v FIG. 5 is a bottom plan view of the bit showing the abrading elements inset therein, and showing the fluid passages on the sides thereof.

With more detailed reference to the drawing, the numeral l designates generally an enlarged bit body having a cylindrical portion 2 and a downwardly and inwardly tapered portion 4i, which portions 2 and 4, as well as the lower face 6 thereof, are covered with hard abrading elements 8, such as diamonds or the like. A cylindrical shank portion liti, which has spanner wrench indentations l2 formed therein, is secured to the upper portion of body l. A threaded stem id is made integral with the shank 10 so `as to be tted into a complementary screwthreaded joint on drill stern (not shown).

The body l has an axial opening lo extending downward through the threaded stem l@ into cavity 17 in the shank portion 10 into the cylindrical portion 2, whereupon a multiplicity, four in the present instance, of fluid passages 1S extend to the lower face 6 of the bit body. Each of the passages l has the lower terminal end thereof interconnecting with a lateral groove passage 2t? or 22, so as to distribute cooling fluid or drilling fluid over the segment in which the particular passage f8 is located. The passages 22 extend inward from the respective passages 18 to t'he axial core receiving hole 2li, so as to supply circulating uid and coolant fluid to the abrading elements which surround and are within the core receiving hole 24, which uid serves to wash the core upward into closed, lateral passage 26, where the core is broken off in a manner which will be brought out more in detail hereinafter.

The closed, lateral passage 26 connects with an enlarged grooved passage 28 formed on the side of the bit body 2 so as to direct the broken core upward by the bit body into the bore hole being drilled.

The present bit is shown to have four abrading segments on the bit body and the lower face thereof, which segments are designated at a, b, c, and d respectively, and which segments have channels 3G, 32, and 34 and 28 therebetween, which channels are of larger cross-sectional area than the grooved passages 2@ and 22, so as to enable the larger or coarser cuttings to be washed into these channels and flushed upward by the drilling fluid to the top of the bore hole of the well. The channel 2S, however, connects with closed, lateral passage 26 to direct the broken cores, which are cut by the abrading elements which surround the axial hole 24, therethrough so as to enable faster cutting action than if all the formation had to be ground into an impalpable powder of a fineness that could be Washed out through grooves 20 and 22.

Further passages 36 are positioned intermediate passages 28, 30, 32 and 34, at least a part of the tapered portion of the bit and Ialong the gauge size portion of the bit to enable further flushing upward of the formation being out, without the formation having to be reduced to a size to pass along the surface by the abrading elements 8.

It is to be pointed out that the passages 30, 32, and 34 increase in cross-sectional area from the lower, innermost portion of the bit body as they radiate outward and extend upward along the face of the bit body portions 4 and 2.

The core receiving hole 24 extends upward centrally of the bit and has abrading elements inset within the walls surrounding the opening and on the upper angular surface which is in axial alignment with core receiving hole 24. By having the upper surface 38 of the portion of the bit body above the core receiving hole 24 arranged at an angle with respect to the axis, the core is readily broken off and passes out through a closed, lateral passage 26 which is closed at the lower end thereof by a bar 40, which bar 40 extends in unitary relation between adjacent segments a and d. The bar 40 holds segments a and d securely together to prevent spreading of the two segments with respect to each other. The opening 26 diverges upwardly and outwardly from the core receiving hole 24 so that any core passing through core receiving hole 24 will be cut off and discharged upward through closed, lateral passage 26 and out through passage 28. By having the bit formed in this manner it gives greater rigidity to the bit and gives a greater surface of abrading elements exposed to the formation, so upon rotation of the bit, nore formation is abraded from the surface acted upon by t e bit.

While the invention has been illustrated and described in some detail in one embodiment thereof, it is to be understood that changes may be made in the minor details of construction and adaptations made to different installations without departing from the spirit of the invention or the scope of the appended claims.

Having thus clearly shown and described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. A drill bit comprising a hollow, threaded member with an enlarged bit body thereon, said bit body having the upper portion thereof substantially cylindrical in form, said enlarged body having an axial opening formed in the upper portion thereof which extends thereinto, said body having a passage extending out of said axial opening to a point on the lower face of said bit body and being off-set laterally with respect to the rotational axis thereof, said bit body having an axial, cylindrical, core receiving hole formed in the lower portion thereof and extending thereinto, a wall encircling said wial, cylindrical, core receiving hole for a spaced distance upward above the lower face of said bit body, said bit body having a closed, lateral conduit leading from said axial, cylindrical, core receiving hole to a side of said bit body, said bit body having an upwardly extending groove formed in the side thereof, the width of which groove is at least as wide as the diameter of said axial, cylindrical, core receiving hole which closed, lateral conduit connects with said groove, and abrading elements inset on the face of said bit and in the wall surrounding said axial, cylindrical, core receiving hole in position to be in contact with the formation being drilled.

2. A drill bit as defined in claim l; wherein said closed, lateral conduit formed in said bit body increases progressively in cross-sectional area as said closed, lateral conduit extends to said upwardly extending groove formed in the side of said bit body.

3. A drill bit as defined in claim l; wherein the outer side of the lower portion of said bit body diverges outwardly and upwardly at an acute angle for a predetermined distance, and wherein the portion of said bit body thereabove is substantially cylindrical in shape.

4. A drill bit as defined in claim 3; wherein the lower face of said bit converges inwardly and upwardly to dene a relatively shallow, conical recess, the surface defining said conical recess covering the greater portion of the area of the lower end of said bit body, the axis of which conical recess coincides with the axis of said axial, cylindrical, core receiving hole.

5. A drill bit comprising a hollow, threaded member with an enlarged bit body thereon, said bit body having the upper portion thereof substantially cylindrical in form, said enlarged bit body having an axial opening formed in the upper portion thereof which extends thereinto, said bit body having a plurality of passages formed therein which extend from said axial opening to a point on the lower face of said bit body, and which passages are offset laterally with respect to the axis of said bit body, said bit body having an axial, cylindrical, core receiving hole formed in the lower portion thereof and extending thereinto, the Wall encircling said axial, cylindrical, core receiving hole being inset with abrading elements for a spaced distance upward above the lower face of said bit body, said bit body having a closed, lateral conduit leading from said axial, cylindrical, core receiving hole to a side of said bit body, said bit body having an upwardly extending groove formed in the side thereof, which upwardly extending groove connects with said closed, lateral conduit, and abrading elements inset on the lower face of said bit and on the exterior, peripheral surface of the bit body in abrading contact with the formation being drilled.

6. A drill bit comprising; a threaded stem, an enlarged bit body on said threaded stem, said stem and said bit body having an opening formed therethrough with the terminal end of said opening lying on the side of the enlarged bit body opposite said threaded stern in offset relation to the rotational axis of said enlarged bit body, said bit body having an axial core receiving hole extending thereinto for a spaced distance, said core receiving hole being formed in same side of said bit body on which said opening terminates, said bit body having a closed lateral passage extending therethrough to the peripheral side thereof, said bit body being of lesser radial dimension from the rotational axis of said bit body to the outer end of said closed lateral passage than the greatest radial dimension from the rotational axis of said bit body to the peripheral face of said bit body, so that when said bit body is within a bore hole of the well, a passage will be formed between the bit body and the wall of the bore hole of the well at such place of lesser dimension, the surface of said body in normal contact with said formation being inset with hard abrading elements.

References Cited in the file of this patent UNITED STATES PATENTS 2,493,178 Williams Jan. 3, 1950 2,614,809 Zublin Oct, 21, 1952 2,931,630 Grady Apr. 5, 1960 2,990,897 Short July 4, 1961 FOREIGN PATENTS 1,083,763 Germany June 23, 1960 1,257,184 France Feb. 20, 1961 

1. A DRILL BIT COMPRISING A HOLLOW, THREADED MEMBER WITH AN ENLARGED BIT BODY THEREON, SAID BIT BODY HAVING THE UPPER PORTION THEREOF SUBSTANTIALLY CYLINDRICAL IN FORM, SAID ENLARGED BODY HAVING AN AXIAL OPENING FORMED IN THE UPPER PORTION THEREOF WHICH EXTENDS THEREINTO, SAID BODY HAVING A PASSAGE EXTENDING OUT OF SAID AXIAL OPENING TO A POINT ON THE LOWER FACE OF SAID BIT BODY AND BEING OFF-SET LATERALLY WITH RESPECT TO THE ROTATIONAL AXIS THEREOF, SAID BIT BODY HAVING AN AXIAL, CYLINDRICAL, CORE RECEIVING HOLE FORMED IN THE LOWER PORTION THEREOF AND EXTENDING THEREINTO, A WALL ENCIRCLING SAID AXIAL, CYLINDRICAL, CORE RECEIVING HOLE FOR A SPACED DISTANCE UPWARD ABOVE THE LOWER FACE OF SAID BIT BODY, SAID BIT BODY HAVING A CLOSED, LATERAL CONDUIT LEADING FROM SAID AXIAL, CYLINDRICAL, CORE RECEIVING HOLE TO A SIDE OF SAID BIT BODY, SAID BIT BODY HAVING AN UPWARDLY EXTENDING GROOVE FORMED IN THE SIDE THEREOF, THE WIDTH OF WHICH GROOVE IS AT LEAST AS WIDE AS THE DIAMETER OF SAID AXIAL, CYLINDRICAL, CORE RECEIVING HOLE WHICH CLOSED, LATERAL CONDUIT CONNECTS WITH SAID GROVE, , AND ABRADING ELEMENTS INSET ON THE FACE OF SAID BIT AND IN THE WALL SURROUNDING SAID AXIAL, CYLINDRICAL, CORE RECEIVING HOLE IN POSITION TO BE IN CONTACT WITH THE FORMATION BEING DRILLED. 